https://journal.ugm.ac.id/v3/JCEF <p style="text-align: justify;">Journal of the Civil Engineering Forum (JCEF) is a four-monthly journal on Civil and Environmental Engineering related sciences. The JCEF is devoted to publish and disseminate research in the fields of structural engineering, geotechnical engineering, water resources engineering, environmental engineering, transportation engineering, and construction management.</p> <p style="text-align: justify;">The particular emphasis of JCEF is given to the civil &amp; environmental researches associated with disasters caused by natural hazards such as geo-disaster (earthquake, landslide, volcanic eruption), water-related disaster (flood, debris flow, coastal disaster, tsunami), and human-made hazards such as soil, water, and air pollution and water scarcity in a tropical region. Articles describing the topics of disaster risk reduction techniques, disaster early warning system, climate change adaptation, vulnerability analysis and trends, pre and/or post-disaster reconstruction and rehabilitation planning and management, forensic engineering, the socio-engineering approach for the countermeasures, or water reuse and recycle are particularly encouraged.</p> <p style="text-align: justify;">JCEF is open access journal and free of charge for submission, publication, and download. There are three categories of articles published in JCEF: Research Articles, Technical Notes, Editorial Note, and Review Articles. The article consists of 6 - 12 pages, 6 - 10 articles per issue, reviewed by selected peer-reviewers.</p> <p>&nbsp;</p> Department of Civil and Environmental Engineering, Faculty of Engineering, Universitas Gadjah Mada en-US Journal of the Civil Engineering Forum 2581-1037 <p>Copyright is granted to authors for the purpose of providing protection for articles written to describe experiments and their results. JCEF will protect and defend the work and reputation of the author and are also willing to address any allegations of violation, plagiarism, fraud, etc. against articles written and published by JCEF.&nbsp; JCEF is published under the terms of the&nbsp;<a href="http://creativecommons.org/licenses/by-sa/4.0/" target="_blank" rel="noopener">Creative Commons Attribution-ShareAlike 4.0 International License</a>&nbsp;(CC BY-SA 4.0). The author holds the copyright and assigns the journal rights to the first publication (online and print) of the work simultaneously.</p> https://journal.ugm.ac.id/v3/JCEF/article/view/18984 <p>Large landslides, triggered by torrential rain or earthquakes, can slide down mountainous slopes and block river channels at the lower end of the slopes. In cases where the landslide volume is relatively small compared to the river discharge, or when the distance between the landslide slope and the river channel is long, incomplete channel blockages may occur due to an insufficient supply of landslide material to fully block the river flow. Since the shape of the channel blockage is the final result obtained through the temporal changes in landslide material movement, river flow, and topography, considering their interactions, it is necessary to investigate the blockage shape by numerical analysis that accounts for these interactions. Therefore, we developed a numerical model to predict the formation of various channel blockages by incorporating the combined conditions of topography, landslide volume, and river discharge. The developed model is a two-dimensional (2-D) model, which can connect several one-dimensional calculation areas for mountainous streams at any selected point in the 2-D area. In addition, the model can consider landslide material movements represented by cylindrical blocks. To verify our model and identify appropriate values for the associated parameters, we investigated the MAE (mean absolute error) for the deposit thickness distribution and the PWO (percentage of the area where the actual and calculated waterlogged areas overlapped) between the actual and calculated results using our model for two previous channel blockages of different sizes. Although our model and the associated parameters still need to be improved by considering the loss of landslide material, they are useful for estimating the magnitude and area of damage caused by large-scale landslides and the associated channel blockage and waterlogging in various river channels with steep side slopes. The calculated results can be utilized in investigating disaster countermeasures for landslides in the area.</p> Takashi Wada Hiroshi Miwa Naoto Aoki Yusei Fujii Copyright (c) 2025 The Author(s) https://creativecommons.org/licenses/by-sa/4.0 2025-07-08 2025-07-08 233 244 10.22146/jcef.18984 https://journal.ugm.ac.id/v3/JCEF/article/view/18988 <p>On November 21, 2022, a M_w&nbsp;5.6 earthquake struck Cianjur, West Java, Indonesia, causing extensive damage to buildings, infrastructure, and public facilities, and resulting in 602 fatalities and thousands of injuries. The earthquake’s hypocenter was located near the Cugenang Sub-District, leading to the identification of the previously unmapped Cugenang Fault as its source. This discovery highlights the need to reassess seismic hazards in the region, as it reveals the existence of previously unrecognized active faults. This study conducts a probabilistic seismic hazard analysis (PSHA) for Cianjur using an updated seismic source model that incorporates the Cugenang Fault. We apply updated ground motion prediction equations (GMPEs) and utilize the logic tree method to account for uncertainties in attenuation equations and source parameters. Ground motion is expressed as peak ground acceleration (PGA) on both bedrock and surface conditions for return periods of 100, 150, 250, 500, 1,000, 2,500, 5,000, and 10,000 years. These return periods capture the hazard levels associated with both frequent low-magnitude and rare high-magnitude earthquakes. Our findings indicate that high PGA values in the Cianjur area are concentrated around crustal faults, exceeding 1.0 g for return periods of 2,500 years and beyond. The Cugenang Fault has a localized impact, with its influence extending up to approximately 10 km from the fault line. A seismic hazard disaggregation analysis confirms that crustal faults are the dominant seismic sources in the region. The results of this study provide valuable insights for updated seismic risk in Cianjur and support future mitigation strategies, urban planning, and infrastructure design to enhance earthquake resilience in the affected area.</p> Yusufa Kholifa Ardha Iman Satyarno Gayatri Indah Marliyani Copyright (c) 2025 The Author(s) https://creativecommons.org/licenses/by-sa/4.0 2025-07-08 2025-07-08 245 256 10.22146/jcef.18988